MetroMPG: If you want to do that, I think the information you've looked at is taking a more complicated route than you need. I'll try to find the web site, but their is another way to do the shape with foam and fiberglass, where you just make the shape, like you want, put fiperglass over the outside, shave/carve the foam on the inside out, down to like a 1/4 inch and then fiberglass over the inside. It gives you the ability to make a one of, that is very strong and you can accomplish those shapes.
I'm off to the Chiropractor, but when I get back later today, I'll try to find the link and post it up.
MetroMPG: Here is the link to the website I was describing. This is for a homebuilt aircraft, but the process and technique is what I think might be what you are looking for. Look at the totally useless box!